@ECHO off
cls
ECHO what is the drive letter windows was installed on while in WinPE.
ECHO Note sometimes this is not on drive C
set /p DRIVE=type the drive letter: 
bcdedit /set {default} device partition=%DRIVE%:
bcdedit /set {default} osdevice partition=%DRIVE%:
bcdedit /set {bootmgr} device partition=%DRIVE%: